You're the best JFC!
Yeah this is a hard question. I was reading the decade rumor thread and someone mentioned they'd like to see a Ryuki vs. Den-O gunform battle and it got me wondering who would win.
Of course I mean a full on fight between the two actual riders (Shinji/Ryuki vs. Ryou/Ryuuta/Den-O) and not some crazy alternate universe Lawyer Ryuki and a Den-O summoned by a card.
After a lot of thought, I think Ryuki would win because of his superior arsenal. His shield could block the bullets until he could close the distance and hack away with dragsaber. Plus you can't count out Dragreder, that's one bad beast. At the same time, Ryuuta's crazy style and and flair might pull off a victory. He is tenacious without a doubt, showed that in his fight against Zeronos. He just wouldn't quit. Still, he doesn't seem to respond too well to taking hits, so I give it to Ryuki.